Electric motor driven material handling system



Sept. 11, 1951 Q GRAY 2,567,883

ELECTRIC MOTOR DRIVEN MATERIAL HANDLING SYSTEM Filed Dec. 22, 1945 4 Sheets-Sheet l IN V EN T 0R. LE] DONALD C. GRAY ATTORNEY Sept. 11, 1951 c, GRAY 2,567,883

ELECTRIC MOTOR DRI VEN MATERIAL HANDLING SYSTEM Filed Dec. 22, 1945 I 4 Sheets-Sheet 2 llllllllli MIIIIIII IIIiIIIL l N V EN TOR. DONALD c app 1y ink/ W A T TOR/YE Y Sept. 11, 1951 c, GRAY 2,567,883

ELECTRIC MOTOR DRIVEN MATERIAL HANDLING SYSTEM 4 Sheets-Sheet 5 ll 1H! ,6 Fig.3

Filed Dec. 22, 1945 INVENTOR. DONALD c. GRAY AT TOR/YE Y D. C. GRAY Sept. 11, 1951 ELECTRIC MOTOR DRIVEN MATERIAL HANDLING SYSTEM 4 Sheets-Sheet 4 Filed Dec. 22, 1945 :J T T1 E 32 QQNXN: mp... Y T \O/I M o2 iW o: I2 W c. M m9 793 02 E 1 .5. 3 0 HR g Z L O i mQ .A HT mo w: /m@ Nv T o. m. Mg m f m2 NON W P ml v Em T: wi WON not 31 $1 Patented Sept. 11, 1951 ELECTRIC MOTOR DRIVEN MATERIAL HANDLING SYSTEM Donald 0. Gray, Rose Township, Ramsey County, Minn., assignor to American Hoist & Derrick (30., St. Paul, Minn, a corporation of Delaware Application December 22, 1945, Serial N0. 636,7 91

(Cl. I'll-$12.)

13 Claims.

This. invention relates to a material handling machine of the general type ordinarily known as cranes or locomotive cranes. As illustrated and described herein, the principles of the invention are applied to a locomotive crane. However, various features of the invention are applicable to other material handling machines and apparatuses of the general nature of cranes and locomotive cranes.

A locomotive or crawler or other type crane used for handling materials ordinarily consists of a crane unit comprising a car having a boom and an electro-magnet and/or bucket or dipper or hook and operating mechanism for the boom and electro-magnet and/or bucket or dipper or hook mounted upon a revolvable platform on the car of the crane, the operating mechanism also being adapted to cause the platform to be revolved so that the boom with electro-magnet and/or bucket or dipper or hook can be swung from side to side of the crane in the operations of removing material from any location about the crane and adjacent thereto. The power plant of the crane frequently is carried by the revolvable platform, and in such case the entire operating mechanism is mounted for relative rotation upon the frame of the car of the crane. In addition to driving the operating mechanism of a crane for its boom, electromagnet and/or bucket or dipper or hook, and for revolving its platform upon the frame of its car, the cranes power plant when upon its revolvable platform sometimes has been connected up to propel the crane unit mechanically and sometimes has been connected up to propel the crane unit electrically along a railroad or other track or surface.

Electro-magnets when employed on cranes for the purpose of transporting or conveying ferrous materials from place to place are suspended from lifting lines which travel upon and relative to booms of the cranes. The electro-magnets are brought into contact with, or dropped upon, the ferrous materials. These adhere to the eIectro-magnets when they are energized and released when the electro-magnets are deenergized. The operating mechanisms of the cranes are employed to cause the electro-magnets, when energized to attract ferrous materials, to be conveyed from one place to another, and when the ferrous materials upon the electro-magnets have reached the locations where they are to be deposited, the electro-magnets are deenergized, by removal of the supply of current to said electromagnets, thus to cause the ferrous materials to be released.

customarily, the prime mover of a locomotive or other crane is, for purposes of convenience andefilcicncy in carrying on the various. functions of the crane, a diesel or other internal combustion or other type engine adapted to. be driven at variable speeds controlled in some suitable and convenient manner by the opera: tor at his will. That is, a usual arrangement is to have the speed of the prime mover or engine of a crane controllable by the operator and the mechanisms for accomplishing various op. erations of the crane, such as swinging, lifting, etc., releasably clutchable to a driven shaftv of said prime mover or engine. In commercial installatlons, the prime movers or engines of cranes are. constructed to be capable of operation throughout a range of widely varying speeds.

A source of, current for an electro-magnet employed in connection with a, locomotive. or other crane, to the purpose hereinbefore mentioned, heretofore has been a direct current generator driven from the prime mover of the crane through the. instrumentality of a flexible chain, belting or gearing. Such. a generator has been of theconstant voltage, constant speed, self-excited type. It is adapted to deliver proper voltage characteristics only while the prime mover operates at substantially constant speed, or varies within but. relatively small limits. With variations. of .the speed of the prime mover, the voltage of a constant voltage, constant speed generator will vary to extent at least as great as the prime mover speed, and, in some instances, will vary as much as. the square of the prime mover speed. In instances when a constant voltage, constant speed generator is operated by a prime mover at higher than the rated speed of the generator, the voltage of course will be higher than normal with tendency toward overheating of an electro-magnet employed, and. obviously, lower than normal voltage will cause a serious reduction in the lifting capacity of the electro-magnet inasmuch as the lifting capacity varies as. the square of the applied voltage.

An improved manner of accomplishing energization of an electro-magnet employed in connection with a locomotive 'or other crane is illustrated and described in my Patent No. 2,370,856. granted March 6, 1945. Stated briefly, the patent mentioned discloses a special generator system driven by the prime mover or internal combustion engine of the crane having a field controlled by means of a separate exciter also driven from said prime mover or internal combustion engine. The generator and exciter are supported upon th rotatable platform of the crane, as is a desirable arrangement. However, in any instance where the type of special generator system of my Patent No. 2,370,856 is employed in connection with a crane also employing an electrical drive for the crane, as is employed in the patent to Ljungkull, No. 2,083,460, granted June 8, 1937, said special generator system constitutes an entity which is independent of and separate from the travel generator of the crane, and the same thing is true of the constant voltage, constant speed, self-excited type of direct current generator, hereinbefore mentioned, when employed to provide a source of current for an electro-magnet of a locomotive or other crane.

Stated broadly, heretofore the source of current for electro-magnets of locomotive or other cranes has been supplied by generators or generator systems independent of and separate from travel generators. It is possible, of course, for an operator of a locomotive or other crane to make manual adjustments of the generator field rheostat of the travel generator of the crane in attempt to maintain constant voltage throughout the various prime mover speeds, but this is completely impractical. Attempts at manual adjustments would result in complications and slowing down of crane operations.

It is desirable that a locomotive or other crane include a single prime mover and a single generator driven by the prime mover suitable to the purpose of supplying power to a travel motor and an electro-magnet of the crane, as well as to the purpose of supplying power to auxiliary motors when employed, thus to reduce the cost of equipment of the crane and the complexity of the equipment and to provide greater simplicity and space around the machinery, and the broad object of the present invention is to provide such a crane. 7

The characteristics which a generator for supplying power to an electric motor for propelling a crane is required to have are considerably different from the characteristics a generator for supplying power to a lifting magnet for a crane must possess. Due to the limited size of diesel and other internal combustion engines,both from the standpoint of cost and space, for use as prime movers of cranes, it is necessary, in order to get high current from the travel generator of a crane to provide high tractive efiort, that there be low voltage, thus to avoid overloading of the prime mover. The output from a travel generator is dependent upon the horsepower from the prime mover. of tractive effort and speed on a travel motor or motors, the characteristics of a travel generator must be such that at high current the voltage is low and at low current the voltage is high, and at no time can the product of voltage times amperes exceed the permissible output of the prime mover. On the other hand, the pick-up power of a lifting magnet varies as the square of the voltage. In order to obtain proper magnet oper ation, the value of the normally applied voltage cannot be too high, lest the magnet become overheated and destroyed, and cannot be below the magnets rating, lest the magnet power be insufficient for its intended purposes. In practical operation of cranes, generators heretofore employed have been unsuitable to use for applying power for both travel motors and lifting magnets under usual conditions of crane use.

magnet lift under all operative conditions as met in practical use of the locomotive or other crane, and also desirably having capacity additionally to supply power for an auxiliary motor or motors, such, for example, as a motor for a fan of a heating apparatus for the crane.

A further object is to providev a material han dling machine of the nature of a locomotive or other crane which will include a prime mover and a generator driven by the prime mover suitable to the purposes of supplying power to a travel motor and to an electromagnet of the crane and which generator will be operative at substantially constant voltage throughout a range of low current values, thus to be capable of supplying suitable current for efiicient magnet operation and at the same time include capacity for flow of sumcient current to said travel motor adapted to obtain relatively low drawbar pull and Therefore, in order to get a wide range A further object of the invention is to provide travel speed when it may be desirable that the crane be transported at low speed while a load is suspended from its electro-magnet, and will be capable of being operative at variable voltages throughout a range of higher current values, thus to include capacity for flow of additional current to said travel motor adapted to obtain comparatively higher drawbar pull or travel speed when it may be desirable that the crane be transported at higher speeds while its electro-magnet has no load.

A further object is to provide a material handling machine of the nature of a locomotive or other crane designed and constructed with the end in view of rendering the material handling machine an improvement in many respects and from various aspects over material handling machines and apparatuses heretofore known for accomplishing the same general purposes.

A further object is to provide a material handling machine of the nature of a locomotive or other crane wherein will be incorporated various desirable and improved features and characteristics of construction which will be novel both as individual entities of said material handling machine and in combination with each other.

And a further object is to provide a material handling machine incorporating features and characteristics of construction as herein illustrated and described.

With the above objects in view, as well as others which will appear as the specification proceeds, the invention comprises the construction, ar-

rangement and combination of parts as now to be fully described and as hereinafter to be specifically claimed, it being understood that the disclosure herein is merely illustrative and intended in no way in a limiting sense, changes in details of construction and arrangement of parts being permissible so long as within the spirit of the invention and the scope of the claims which follow.

In the accompanying drawings forming a part of this specification,

Fig. 1 is a side elevational view of a material handling machine made according to the invention, parts being broken away;

Fig. 2 is an enlarged top plan view of the machine, parts being omitted;

Fig. 3 is a detail sectional view, taken substantially on line 33 in Fig. 1;

Fig. 4 is a fragmentary enlarged top plan View of the machine;

Fig. 5 is a detail sectional view, taken on line 5-5 in Fig. 4;

Fig. 6 is a detail sectional view, taken substantially on line 56 in Fig. 2; and Fig. 7 is a diagrammatic view of an electric wiring system of the machine.

With respect to the drawings and the numerals of reference thereon, the locomotive crane disclosed includes a car body or truck consisting of a frame I having bearings H for front and rear axles |2 rigidly supporting travel wheels l3. As shown, there are two front and two rear axles |2 each supporting oppositely disposed traveling wheels 3. Coupling members l4 upon the car body or truck frame H! are for the purpose of coupling the locomotive crane with a different vehicle or car, which in some instances may be propelled by the locomotive crane, and in some instances may propel said locomotive crane.

The car body or truck frame In supports a platform or deck I5 which is rotatable on said car body or truck frame. As shown, the platform or deck |-5 includes a vertical, hollow, downwardly extending entity I6 which extends into a hollow portion ll of the car body or truck frame.

A circumferential portion of the platform or deck I5 includes conveniently mounted rollers spaced about said platform or deck and concentric with the vertical, hollow entity IG, said rollers being supported upon and ridable upon or over a bull gear l8, which also is concentric with said vertical, hollow entity I6 and is fixedly attached to the car body or truck frame It) in any suitable and convenient manner.

A boom of the crane, upon the rotatable platform or deck I5, is designated I9. The boom may be of usual or preferred construction. Said boom |9 is suitably and conveniently pivoted upon a part of the platform or deck l5. A mast (not shown) of usual or preferred construction also may be arranged upon the rotatable platform or deck. A cable 20 is for the purpose of accomplishing hoisting or raising and lowering operations of the boom l9. A drum 2| for actuating the cable 29 is mounted upon the rotatable platform or deck. As shown, the cable 23 has one of its end portions wrapped about the drum 2|, and said cable 20 extends over pulleys 22 supported in ordinary or preferred manner. The end portion of the cable 29 opposite the drum 2| is assembled with the boom l9 in ordinary or preferred manner, as denoted generally at 23. When the drum 2| is rotated in direction to wind the cable 29 thereon, the boom is hoisted or raised, and when said drum 2| is rotated, or allowed to rotate. in opposite direction said boom is lowered by gravity.

A cable 24 extends over a sheave 25 upon the outer end of the boom I9 and supports a hoisting hook 25. In turn, the hoisting hook 25 supports an electromagnet 21. A drum 28 for actuating the cable 24 also is mounted upon the rotatable platform or deck l5.

Said rotatable platform or deck l5 suitably and conveniently supports a power plant or prime mover, which is, as disclosed, constituted as an internal combustion engine 29 of the diesel type. The internal combustion engine 29 includes a driven shaft 30 which is conveniently and desirably flexibly connected, as represented generally at 3|, to the driving shaft 32 of the generator 33. The generator 33 also is suitably supported upon the revolvable platform or deck I5, and said internal combustion engine 29 and said generator 33 of course are rigidly secured to said platform or deck. The generator 33 desirably is of that type designed for drooping characteristics of the generator volt-ampere curve and wherein the voltage is high for low current and low for high current. As disclosed; the generator 33 includes a driven shaft 34, arranged opposite the internal combustion engine 29, which fixedly supports a sprocket wheel. A sprocket chain 35 rides over the sprocket wheel upon said driven shaft 34 and also rides over a sprocket wheel fixed upon a horizontal shaft 35 suitably and conveniently mounted upon the platform or deck l5. The horizontal shaft 36 releasably carries a small gear 31 which meshes with a larger gear 38 fixed upon a horizontal shaft 39 suitably and conveniently mounted upon the platform or deck l5. The gear 38 meshes with a gear 49 fixed upon a horizontal shaft 4| at the side of the horizontal shaft 39 opposite the horizontal shaft 35. Said horizontal shaft 4| also is suitably mounted upon the rotatable platform or deck l5. It will be seen that when the horizontal shaft 39 is driven by the internal combustion engine 29, through the instrumentality of the sprocket chain 35, the horizontal shaft 36 and the gears 3'! and 38, the horizontal shaft 4| will be driven through the instrumentality of said gear 33 and the gear 411.

The drums 2| and 23 are carried by the hori-' zontal shaft 4| and are normally loose on said mentioned horizontal shaft. Said drums 2| and 28 are adapted to be rotated, independently of each other, with said horizontal shaft 4|. A clutch, denoted generally at 42, is for the pur-' pose of clutching the drum 28 to the horizontal shaft 4|, and a clutch lever 43 is for actuating said clutch 42 to operative and inoperative positions. A clutch, denoted generally at 44, is for the purpose of clutching the drum 2| to said shaft 4!, and a clutch lever 45 is for actuating said clutch 44 to operative and inoperative positions. In the disclosure as made, the clutches 42 and 44 are of air actuated type and are oper ated in well known manner requiring no further description herein.

Each of the drums 2| and 29 is as disclosed provided with a brake 45. The brakes 45, 45 may be of well known construction. Numeral 41 indicates a braking pedal for operating the brake 49 associated with the drum 2!, and 48 designates a braking pedal for operating the brake 49 associated with the drum 2B.

The horizontal shaft 39 conveniently supports oppositely disposed bevel gears, represented 49 and 50, respectively, each normally loose on said horizontal shaft 39. The bevel gears 49 and 59 mesh with a bevel gear 5| fixed upon a vertical shaft which drives a vertical shaft 52 suitably mounted in bearings fixed upon the rotatable platform or deck |5. Said vertical shaft .52 fixedly carries a pinion 53 which meshes with the teeth 54 of the bull gea I8. The bevel gears 49 and 50 mesh with portions of the bevel gear 5| at opposite sides of its vertical shaft, and clutches 55, 55 are for separately clutching said bevel gears 49 and 5!] to said horizontal shaft 39. A single clutch lever 56 is for actuating each of the clutches 55, the arrangement being such that both clutches 55, 55 may be inoperative, or either one, but not both, operative to clutch one or the other of the bevel gears 49, 59 to the horizontal shaft 39. Evidently, when the bevel gear 49 is clutched to the horizontal shaft 39 and said horizontal shaft is rotated, the bevel gear 5|, with the vertical shaft 52 and the pinion 53, will be rotated in one direction, and when the bevel gear 59 is clutched to said h'ori zontal shaft 39 and the horizontal shaft is rotated, said bevel gear with the vertical shaft 52 and the pinion 53, will be rotated in opposite direction. Rotation of the pinion 53 in either direction obviously will cause the platform or deck I5 to be rotated about its vertical axis in direction to correspond, by reason of the engagement of said pinion 53 with the teeth 54 of the bull gear I8. The specific arrangement selectively for clutching the bevel gears 49 and 50 to the horizontal shaft 39 is well known and requires no fuller description herein. In the disclosure as made, the clutches 55, 55 are of air actuated type.

A brake for the horizontal shaft 39, and hence for the rotatable platform or deck I5, may be of any suitable construction, and said brake may be actuated by means of a braking pedal 51, similar to the braking pedals 41 and 48. A brake such as mentioned for said horizontal shaft 39 is ordinary equipment of machines of the present general character, and, therefore, requires no further description herein.

The clutches 42 and 44 may be inoperative when the brakes 46, 46 are applied to the drums 28 and 2|. In addition, any suitable type of means well known in the present art may be included for disconnecting the horizontal shaft ll from driving connection when a brake is applied to either drum 2| or 28. Also, a suitable type of well known means will be included for disconnecting the horizontal shaft 39 from driving connection when the brake for said horizontal shaft 39 is applied. A clutch for connecting the small gear 31 to and disconnecting said small gear from the horizontal shaft 36 is denoted 58. As disclosed, the clutch 58 is of air actuated type. A clutch lever for actuating the clutch 58 is represented 59.

It will be evident from the description thus far given, that the clutch 58 can be manipulated to disconnect the small gear 31 from the horizontal shaft 36 so that said small gear 31 and all of the parts driven thereby will be stationary. When the clutch 58 connects the small gear 31 to the horizontal shaft 36, said small gear 31 will be driven to rotate the larger gear 38 and the horizontal shaft 39 upon which said larger gear 38 is fixed when the internal combustion engine 29 is operative. When said horizontal shaft 39 is rotating, the drums 2| and 28 and the vertical shaft 52 can each be stationary or in motion, all independently of each other, and said vertical shaft 52 can be rotated in either direction, necessary or preferred at some particular time. And all of the brakes and clutches are capable of independent actuation, the operating parts being adapted satisfactorily to accom-- plish all of the working operations in the machine except those necessary to propel said machine.

The locomotive crane is adapted to be propelled by electric motive power, the machine including a pair of electric motors, each designated 60, as shown, although a single electric motor, or more than two electric motors, could be employed. The electric motors 60, 60 are adapted to be actuated or driven in either direction by the generator 33. Each electric motor 69 is conveniently and flexibly attached to the underside of the car body or frame IE1 at location adjacent an axle H. to be driven. As shown, an interior end portion of each electric motor 60 is rotatably mounted, as at 6|, upon an outermost axle I2, and an exterior end portion of each electric motor is pivotally sup- .disclosed in Fig. 3, of the drawings.

ported, as at 62, upon a transverse bar 63 at an end of and extending from side to side of the car body or frame II]. The construction and arrangement will be such that the electric motors 60,. are resiliently connected with the transverse bars 63, 63. The shaft of each electric motor 68 fixedly carriesa pinion 68 which meshes with a gear 65 fixed upon the axle I 2 which supports the corresponding electric motor.

The electric motors 69, 68 are of the reversing type, and a'controller or master switch 66 for said electric motors is suitably and conveniently mounted upon the revolvable platform or deck I5. The controller or master switch 66 may be of any construction suiting it to its purposes. It includes a control lever 6'! adapted to be manipulated to selected positions to close various different circuits for the electric motors 60, 60 adapted to cause said motors to be driven at predetermined and preferred speed in either direction. A series of lead wires, including a sufficient number suitable to the purpose, extend between the generator 38 and the controller or master switch 66. The connection of said mentioned lead wires between said generator 33 and said controller or master switch 66 can be made in ordinary manner, both said generator and controller or master switch being carried by the platform or deck I5 and movable therewith, and being supported in stationary relation to each other.

As will be apparent, the electric motors 60, 68 being fixed upon the car frame I0, and the controller or master switch 66 being fixed upon the revolvable platform or deck I5 in spaced relation to the vertical axis thereof and movable with said platform or deck, an arrangement of conducting connections between said controller or master switch 66 and electric motors 60, 60 which has no loose and dangling lead wires is desirable, although it is to be understood that the lead wires between the controller or master switch and the electric motors could be continuous in appropriate manner, suflicient slack in the connections of course being permitted to allow for the revolving movements of the platform or deck I5. Numeral 68 denotes a contact element assembly for making connections between the controller or master switch 66 and the electric motors 60, 60. Said contact element assembly 68, or equivalent, making provision for neat, practical and vastly more satisfactory conducting connections, is greatly to be preferred.

The contact element assembly 68 is very clearly As there shown, an annular, horizontal extension 69 of the vertical, hollow entity I6 integrally supports downwardly extending, vertical bolt members 10, 18 which in turn support a circular, horizontal plate H. Tubular insulation upon the bolt members 10, i8 is denoted I2.

A series of contact rings 13 are arranged in overlying relation to each other between the horizontal extension 69 and the horizontal plate II and rigidly supported by said extension and plate in spaced, surrounding relation to the bolt members l9, 18. A series of separator insulating discs 14 are arranged between each pair of adjacent contact rings 13 and between the uppermost and lowermost contact rings and said extension 69 and plate 'lI. Annular spacers of the extension 69 and the plate H are denoted 15.

A series of connector rods 16, including a connector rod 16 for each contact ring, extend in spaced relation to each other through the vertical, hollow entity I6 and the annular, hollow exmzm m tension 69, as well as through a greater or less number of the contact rings 13 and insulating discs 14. Each connector rod 16 is secured. to a corresponding contact ring .13 and isv in spaced or insulated relation to all contact rings except the one to which connected. The upper end of each connector rod 16 is separately attached to a lead wire from the controller or master switch 58.

The contact element assembly 68 also includes spaced apart contact brushes 11, one in engagement with each contact ring 13. Said contact brushes 11 can be of any ordinary or preferred construction. As shown, each contact brush 11 is carried by a holder 18 therefor, and said holders 18 are suitably fixed in spaced relation to each other upon a vertical pipe 19 itself suitably supported by the car body or frame I 0. More explicitly, the upper and lower ends of the vertical pipe 19 are supported in upper and lower annular elements, respresented 80 and 8|, respectively, and tubular insulation 82 upon said vertical pipe 19 retains the holders 18 and one side of the annular elements 80 and 8| in fixed, spaced apart relation. Said annular elements 80 and 8| are retained in fixed, spaced apart relation at their opposite side by a headed and nutted bolt 83 and a tubular spacer 84 upon said bolt and between the annular elements 80 and BI. The inner margin of the upper annular element 80 engages the outer margin of the annular, horizontal extension 69 beneath an annular flange 85 upon said annular, horizontal extension 59, the inner margin of the lower annular element 8| engages the outer margin of the circular, horizontal plate 1| v above an annular flange 85 upon said circular, "horizontal plate, and the circular, horizontal plate is anchored to the car body or frame as denoted at 81. The brush holders 18 support lead wires which are appropriately connected to the electric motors 50, 50. Said brush holders and electric motors obviously having stationary or fixed relation with respect to each other, the connections for both ends of the lead wires between the brush holders and the electric motors can be ordinary binding post connections.

It will be seen that the parts of the contact element assembly 68 which move relative to each other in practice are a unitary structure including the contact rings 13 which are rotatable relative to the contact brushes 11, and said contact brushes 11 ride said contact rings 13 as these rotate, continuously to provide conducting capacity for electrical current between each of the lead wires to the contact element assembly 68 and the corresponding lead wires from said contact element assembly.

A brake of any suitable construction for the traveling wheels I3 may be employed, and the locomotive crane may include a braking lever 88 for such a brake; or the locomotive crane may incorporate a usual or preferred type of air brake adapted to be actuated by air pressure provided by an air compressor such as denoted at 89. The

air compressor 89 may be of any construction platform or deck I5 is indicated 92, and a heating apparatus, also upon said platform or deck, is designated 93'. An auxiliary electric motor 94 is for driving a fan (not shown) of the heating 10 apparatus. 93. The auxiliary electric motor 94 is supported upon said heating apparatus 93.

A small generator 95. of special design and for :a purpose to be made plain, is mounted upon the rotatable platform or deck I5. Said small generator 95 is adapted to be driven, as by the belt 96, from the driving shaft 32 of the generator 33.

The prime mover or internal combustion engine 29 is adapted to cause or be capable of causing mechanism for accomplishing ordinary operations of the locomotive crane to be actuated, and said prime mover or internal combustion engineadditionally is adapted to cause or be capable of causing the small generator 95 and the generator 33 to be driven. The generator system of the machine is adapted to cause or be capable of causing the travel electric motors 59, 50, the electromagnet 21 and the auxiliary electric motor 94 to be energized.

The controller or master switch 66 is a reversing type drum master switch. It includes a plurality of conducting segments 91, 98, 99, I00 and I9], and a plurality of conducting segments I62, I83, I84, I05 and I06. A conductor between t nductin segments 91 and I02 is denoted I61, conductors between the conducting segments 91, 98, 99, I88 and IIJI are indicated I68, and conductors between the conducting segments I32, I03, I04, I and I05 are denoted I09. The controller or master switch 66 additionally includes conducting segments III! and III, and also includes a plurality of fingers H2, H3, H4, H5, H8, H1, II8 and H9.

The generator 33,.is adapted to be connected through conductors I20 and I2I and I22 and I23, by means of reversing contactors I24 and I25, through the slip rings 13 and control brushes 11 to the electric motors 58, 50. Closing of the contactor I24 is adapted to cause the electric motorsfifl, 88 to be energized for rotation in direction to drive the locomotive crane in one direction, and closing of the contactor I25 is adapted to cause said electric motors to be .energized for rotation in direction to drive said locomotive crane in opposite direction.

Resistors, denoted I26 and 121, respectively, are adapted to be connected in circuits for the electric motors 69, .60. A contactor I30 is for connecting the resistor I21 in parallel with the resistor I26, and a contactor I3-I is for short circuiting the resistors I25 and I21.

Resistors I28 and I29 are adapted to be connected in the circuit for a generator shunt field I39. A contactor I32 is for short circuiting the resistor I28 and a contactor I33 is for short circuiting the resistor 129.

In the illustrated embodiment of the invention, the small generator a regulator which may include three or more fields, but in instances where preferred the small generator or regulator may take other forms and yet perform the functions as hereinafter described. One field I34 of the generator or regulator 95 is a shunt field responsive to the voltage generated by an armature I35. Operation of 1a -.contactor I48 opens this field to make the generator inoperative. A second shunt field I33 of said gen.- erator or regulator :95 is excited "from .a refer.- ence source which in the present disclosure a constant potential battery I31. A third shunt field I38 of the generator or regulator .95 is connected across the terminals of the generator 33 and is the control field of said generator 33. The fields I35 and I38 are differential with respect to their magnetic .fiuxes so that should the 11* field'l38 become higher thanthe field I36 a voltage will be generated in the armature I35 of such direction as to reduce the current flowing in the main generator field and thus reduce the. voltage generated -by the generator 33. Should the effect of the field I38 become less than the efiect of the field I36, a voltage will be generated in the armature I35 of such direction as to increase the current in the main generator field andthus increase the voltage generated by the generator 33. The shunt field I34 amplifies the effect of the two fields I36 and I38 and thus is provision for slight differences between fields I38 and I36 producing great changes in voltage generated in the armature I35. The design of the small generator or regulator 95 is such that the voltage of generator 33 can: be maintained at a constant value.

A conductor I4I extends between the reversing contactor I 24 and the finger II2. A conductor I42 extends between the reversing contactor I25 and the finger II3. A conductor I43 extends between the contactor I30 and the finger II4. A conductor I44-extends between the contactors I3I and I40 and the finger II5. A conductor I45 extends between the contactor I32 and the finger II6. A conductor I46 extends between the contactor I33 and the finger H1.

The field I36 is connected to the battery I31 by conductors I41 and I48. A conductor I49 extends between the contactor I24 and the battery I31.v A conductor I50 extends between the contactor I25 and the conductor I49. Conductors II and I52 extend between the contactors I30 and I3I and said conductor I49. Conductors I53 and I54 extend between the contactors I32 and I33 and the conductor I49. A conductor I55 extends between the conductors I08 and the conductor I41. 7

A magnet controller of the machine includes a line contactor I56 for connecting the electromagnet 21 to theleads of the generator 33, a line resistor I51 and a drop contactor I58.

An interlock of said machine, denoted generally at I59, is interposed between the magnet controller and the controller or master switch 66. A cam I60 of the interlock- I59, integral with the control lever 61 for the master switch 66, is rotatably supported, as at I6I, in any suitable and convenient manner, upon the revolvable platform or deck I5, and a solenoid I62, also suitably and conveniently supported upon said revolvable platform or deck, has an armature I63 adapted to lie inthe path of spaced apart limit surfaces I64, I64 of said cam I60 when said solenoid I62 is energized. A curved lever I65 is rigid with the control lever 61 to be swung upwardly and downwardly with swinging of said control lever 61 from side to side, a straight actuating lever I66 for the travel controller or master switch 66 is suitably and conveniently assembled with said travel controller or master switch, and a rigid link I61 is connectedbetween the outer or free ends of the curved lever I65 and the straight actuating lever I66. The construction and arrangement are such that the control lever 61, and hence the actuating lever I66, can be swung through a substantially unlimited are when the solenoid I62 is de-energized, but can be swung through only a limited are when said solenoid I62 is energized. The are through which said control lever 61 can be swung of course will be limited by engagement of one or the other of the limit surfaces I64, I64 with the armature I63 when the solenoid I62 is energized. The farther apart said 12 limit surfaces I64, I64, the greater the magnitude of the are through which the control lever 61 can be swung when the solenoid I62 is energized, and vice versa, as will be obvious.

It should be remarked that interlocking could be accomplished in a manner different from that disclosed.

A pilot circuit button I68 is adapted manually to be actuated to cause a normally open switch I69 to be closed and a normally closed switch I10 to be opened, and a push button I1I is adapted manually to be actuated to cause a normally open switch I12 to be closed.

Conductors I13 and I14 extend from the conductors I20 and I2Ito switches I15 and I16 controlled by the line contactor I56, and conductors I11 and I18 extend from said switches I15 and I16 to the electromagnet 21.

Conductors I19 and I including the line resistor I51 extend from the conductors I13 and I14 to switches I8I and I82 controlled by the drop contactor I58, and conductors I83 and I84 extend from said switches I8I and I82 to the conductors I18 and I11.

Conductors I85 and I86 extend from the conductors I13 and I14 to the auxiliary electric motor 94, and said conductor I86 includes a regulator I81 for said auxiliary electric motor.

The resistor I26 is included in a conductor I88 extending between switches controlled by the contactors I24, I25 and I30, I3I, respectively, and the resistor I21 is included in a conductor I89 extending between the conductor I88 and the switch controlled by said contactor I30.

The resistors I28 and I29 are included in a conductor I90 extending between the conductor I14 and the field I39. A conductor I9I extends from a portion of the conductor I90 between said resistors I28 and I29 to a switch controlled by the contactor I33, and a conductor I92 extends from a portion of the conductor I90 between the resistor I28 and said field I34 to a switch controlled by the contactor I32. A conductor I93 extends from the field I34 to a switch controlled by the contactor I40, and a conductor I94 extends from said last mentioned switch to the The field I38 is included in a conductor I95 extending between the conductor I14 and the conductor I20, and said conductor I95 includes a resistance I96. The armature I35 is included in a conductor I91 extending from the conductor I90 to the conductor I94, and a conductor I98 extends from the field I39 to the conductor I95.

A conductor I99 extends between the conducting segment III! and the conductor I2I, and a. conductor 200 extends between the normally open switch I69 and the conducting segment I I I.

A conductor 20I extends from said normally open switch I69 to the line contactor I56, a conductor 202 extends from said line contactor I56 to the solenoid I62, and a conductor 203 extends from said solenoid to the conductor 20I.

A conductor 204 extends between the normally closed switch I10 and a portion of the conductor I95 between the resistance I96 and the conductor I14, and a conductor 205 extends between said normally closed switch I10 and a portion of said conductor I95 between the field I38 and said resistance I96.

A conductor 206 extends from the conductor 200 to the normally open switch I12, a conductor 201 extends from said normally open switch I12 to the drop contactor I58, a conductor 2I0 75 extends from said drop'contactor I58 to the line 13 'ontactor I56, a conductor 2-I'3 extends from the conductor I to a switch 2I4 controlled by the drop contactor I58, and a conductor 2I5 extends from said switch 2 I4 to the conductor H8.

The invention herein disclosed presents a locomotive crane or other crane which includes a prime mover and a generator driven by the prime mover suitable to the-purpose of supply ing power to drive travel motors employed in connection with a crane and to the purpose of supplying power for energizing an electro-magnet of the crane, as well as to the purpose of su'pplying power to auxiliary equipment, such as the auxiliary electric motor 94, when employed in connection with a crane.

It will be apparent from Fig. 2 of the drawings that the internal combustion engine 29,- the gen orator 33, the auxiliary electric motor 94, the small generator 95 and the mechanism of the crane for accomplishing hoisting, swinging, etc., are all upon the rotatable platform or deck I5.

The generator 33 is adapted to be operative at substantially constant voltage throughout a range of lower current values to be capable of supplying suitable current for eificient operation of the electro-magnet 21 and at the same time include capacity for fiow of sufficient current to the electric motors 60-, 60 adapted to obtain relatively low drawbar pull and travel speed or the crane when it is desirable that the crane be transported at low speed while a load is suspended from the electro-magnet 21, and said generator 33 is adapted to be capable of being operative at variable voltages throughout a range of higher currentsto include capacity for flow oi'additional current to said electric motors 60, 30 adapted to obtain comparatively higher drawbar pull and travel speed when it may be desirable that the crane be transported at higher speeds while its electro-magnet has no load.

When the master switch 66 is in neutral position, as said master switch is disclosed in Fig. '7 of the drawings, the control lever 61 is vertical position, as said control lever is disclosed in Figs. 2 and 6, both of the reversing contactors I24and' I25 are in open position, and all of the parts of the electrical system of the machine are situated as in said Fig. '7

The construction and arrangement will be such that when the internal combustion engine -23 is operating at its governed speed, the generator 33 will be supplying a substantially constant voltage maintained by the small generator or regulator 95, and when the control lever 51' is moved to actuate contacts in ,the' master switch 96, the excitation of the field of said generator 33 will be varied thus to vary the current through the travel electric motors 0, 60. The

Voltage output of the generator 33 is adapted to be maintained substantially constant over a lim ited current range of said generator 33.

When the master switch 66 is moved to the first position forward, the conducting segment I32 becomes engaged with the finger I I2 and the contactor I24 becomes energized from the bat- "generator 33 while current and voltage across the-crave motors 59,50 is a itifictldhdf the dif Stated otherwise,- the difference in vo1tage at-the terminals of the generator 33 and the Voltage across th travelmeters 60; 60 when the master switch 56 is moved to the first position forward isabsorbed by the resistor I26.

when the masterswiteh is moved to the sec= end position forward, the conducting segment I03 becomes engaged with the finger H4 and the contactor I becomes energized to cause the switch controlled by said contactor I30 to become closed. thus to connect the: resistor I21 inpar allel with the resistor I20 and cause the total resistance in series withthe armatures of the travel motors 60, 60 to become reduced. While the power transmitted to the travel motors 60, 69 is increased in response to movement or the master switch 66 to the second position forward, thus to cause greater drawbar pull or speed of operation of said travel motors," the voltage at the voltage at the terminals of the generator 33 is maintained atconstant value by the small generator or regulator 95. The difference'in volt age at the terminals of said generator 33 and the voltage across said travel motors 6'0, is absorbed by the resistors I26 and I21 acting in parallel.

When the master switch is moved to the third position forward, the conducting segment I04 becomes engaged withthe finger H5 and the contactor I3I becomes energized to cause the switch controlled by said contactor I 3i to become' closed, thus to short circuit the resistors I26 and I21 and connect the travel motors .60., 60 directly to the generator '33.- The auxiliary contactor I40 is energized upon energization of the contactor I3 I to cause the field I34 of the small generator or regulator 95 to be Opened thus to render said small generator or regulator inoperative. The current and voltage across the travel motors 60, 60 becomes that of the genorator 33 upon opening of said field I34. Evi 'dently, the power transmitted to the travel mo"- tors 60, 60 will be increased upon movement of the master switch to the third position for- Ward by reasonof short cir'cuiting of the re sisters I26 and I21.

When the master switch '66 is moved to the fourth position forward, the conducting segment I05 becomes engaged with the finger H6 and the contactor I32 becomes energized to cause the switch controlled by said contactor I32 to be come closed, thus to short circuit the resistor I'28. The reduction in the resistance of the field circuit I39 as a consequence to short circuiting the resistance I28 causes an increase in voltage and current across the travel motors I511, 60.

When the master switch 66 is moved to the fifth position forward,- the conducting segment I05 becomes engaged with the finger I I1 and'the contactor I 33 becomes energized to cause the switch controlled by said contactor I33 to become closed, thus to short circuit the resistor I29.

' The reduction in the resistance of the field circuit I39 as a consequence to short circuiting the resistor I29 causes an increase in voltage and current across the travel motors 60, 60.

It will be obvious that the description given with respect'to the manner of operation of the travel motors 60, upon forward advancement of the master switch 66 from position to position also applies with-respect to the mannerof operation of said travel motors upon rearward advancement of said master switch, except that atlthe first position rearward the conducting segment 91 willbecome engaged with the finger H3, and the contactor I will become energized to; close the switches controlled by said controlled by said contactor I25 thus to cause operation of the travel motors to be reversed, atthe second position rearward the conducting segment 98'will become engaged with the finger H4, at the third position rearward the conducting segment 99 will become engaged with the finger I I5, at the fourth positionrearward the conducting segment I06 will become engaged with the finger H6, and at the fifth position rearward the conducting segment IIlI will become engaged with thefinger H1.

While in the illustrated embodiment of the invention, the generator includes in-built characteristics for obtaining the desired characteristics for the third, fourth and fifth positions forward and reverse of the master switch 66, these same characteristics could be provided by means of a regulator functioning after the fashion of the regulator 95. r

gThe electro-magnet 21 can be energized only when the master switch 66 is in its neutral position or in its first or second positions forward or reverse. The circuit for the normally, open switchI69 is through the conducting segments H0 and III, and, therefore, can be established when, and only when, said master switch 66 is in I one of the positions mentioned; viz., neutral position or first or second position forward or reverse. Obviously, the fingers I I8 and H9 will be clear of the conducting segments H0 and III when the master switch 66 is in third, fourth and fifth positions forward and reverse. It will be apparent that said conducting segments I I0 and III could be shorter to be clear of said fingers H8 and H9 when said master switch is in second position forward and reverse; or the conducting segments could be longer so as to engage the contact fingers H8 and H9 when the master switch is in third, or even fourth, position forward and reverse.

vDepression of the pilot circuit button I68. to cause the normally open switch I69 to be closed will complete a circuit from the generator 33 through the conducting segments III), III and said switch I69 to the line contactor I56. Energization of said line contactor I56 will cause the switches I15 and I16 to be closed thus to connect the electro-magnet to the conductors I13 andI'M supplied from said generator 33, which, in turn, has its voltage maintained at a constant value by the small generator or regulator 95, whether or not the travelmotors 66, 68 are energized.

The normally closed switch I18 is opened in response to depressing movement of the pilot circuit button I68 which causes the 1 normally open switch I69 to be-closed, and with opening of said normally closed switch I16 the resistance I96 is inserted in the field I38 of the small generator or regulator 95 thus to cause increased voltage, or voltage greater than normal, to be maintainedon the generator 33. Such increased and the circuit of the field I38 is returned to normal so that the voltage output of the generator 33. is immediately .returned to its normal :valueby the small generator or regulator 95. 7

i6 7 A" holding circuit for the line contactor I56 is completed upon energization of said line can: tactor, said holding circuit being traced from they conductor I14 through the closed switch I16 and the conductors I18 and 2I5 to the closed switch H4, and thence through the conductor 2I3 to the line contactor I56. Thus, said line contactor I56 will remain closed after the switch I69 is opened. It will be evident that as long as the pilot circuit button I68 is held depressed to cause the normally closed switch I16 to be open, not only will the electro -magnet 21 be and remain energized, but also the voltage appliedto said electro-magnet will be increased. Also it will be evident that the solenoid I62 of the'interlock I59 will become energized simultaneously with energization of the line contactor I56 and will remain energized as long as said line con v tactor remains energized. A circuit for said solenoid I62 which is closed when the line contactor I56 is energized is traced from the conductor I14 through the switch I16, the conductors I18 and 2 I 5, the closed switch 2 I4 and the conductors 2I3, 2III and 203 to said solenoid I62, and thence through the conductor 202 to the conductor I13. The adjacent end portion of the armature I63 is adapted to lie between and in the path of the limit surfaces I64, I64 of the cam I60 at all times while the solenoid I62 is energized, thus to limit the extent to which the control lever 61 can be swung. In the disclosure as made, the cam I60 is adapted to permit swinging movement of the control lever 61 between its position when the master switch 66 is at second position for ward and its position when said master switch is at second position reverse. The limit surfaces I64, I64 of said cam I60 could, however, be spaced apart a shorter distance to limit swinging movement of the control lever 61 to capacity for travel between the position of said control lever when the master switch is at first position forward and the position of said control lever when said master switch is at first position reverse; or said limit surfaces I64, I64 could be spaced apart a longer distance to permit swinging movement of the control lever 61 between the third, or even the fourth, positions forward and reverse of the cause a reverse flow of current through the electro-magnet 21 and opening of the switch 2I4 will cause the line contactor I56 to be deenergized thus to cause the energizing circuit, including the switches I15 and I16, through said electromagnetto be broken but an instant after reverse flow of current through the electro-magnet by way of the switches I8I and I82 is accomplished.

Upon release of said push button I1I said nor-- mally open switch I12 will become opened, to break the circuit to the contactor I58. Thus the switches I8I and I82 in the reverse circuit. for the electro-magnet 21 will become open.

' It will be apparent that de-energization of the line contactor I56, by reason of opening of the switch 2I4 due to energization of the drop contactor I58 in response to closing of the normally open switch I12, alsorwill cause the solenoidI62 to becomede-energized thus to cause or permit the armature I63 to be moved to position where it will be clear of the limit surfaces 164, I64 of the cam I60.

The generator system of the invention, including the generator 33 and the small generator or regulator 95, is equipped to be capable of supplying power suitable for operation of the electric motors 60, E and also to be capable of supplying power suitable for the electro-magnet 2i. Said generator system is so constructed that it can function as a travel generator having characteristics making it possible that at high current the voltage will be low and at low current the voltage will be high, and the generator system also is so constructed that it can function as a lifting magnet generator having characteristics making it possible that the value of the normally applied voltage will be substantially constant.

It is considered that when auxiliary motors, such as the auxiliary electric motor 84, are to be operated from a locomotive crane generator system adapted to function after the manner of the generator system disclose-d, said auxiliary motors may be operated under all conditions of voltag of said generator. Ordinarily, the generator 33, connected to the auxiliary electric motor 94 through the regulator I37, \vil operate at constant voltage. Should it be desirable to operate auxiliary electric motors, such as the auxiliary electric motor 94, while a generator such as the generator 33 is operating under variable conditions, the auxiliary electric motors employed can be of such design that they will be successfully operable within the variable voltage range encountered.

What is claimed is:

1. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits for said motor and electromagnet, a controller adapted to be advanced step by step from a neutral position to different operative positions to cause circuits for transmitting power of increasing value to said motor successively to be closed, acontactor for controlling a circuit to include said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, and an interlock operable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance or" a selected operative position.

2. In combination, a prime mover, a generator driven thereby, an electric motor, an electro-magnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to diiierent operative positions to cause circuits for transmitting power of increasing value to said motor successively to be closed, a contactor for controlling a circuit to include said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, an interlock perable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position, and means for rendering said contactor incapable of closing said electro-magnet circuit when said controller is situated at any of its operative positions in advance of said selected operative position.

3. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to difierent operative positions to cause circuits for transmitting power of increasing value to said motor successively to be closed, a contactor for controlling a circuit including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, and an interlock constituted as a solenoid in said contactor circuit and a stop element rigid with said controller operable when the contactor is conditioned to cause said electrmmagnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position.

4. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to different operative positions to cause circuits for transmitting power of increasing value to said motor successively to be closed, a contactor for controlling a circuit including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, an interlock constituted as a solenoid in said contactor circuit and a stop element rigid with said controller operable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position, and means for rendering said contactor incapable of closing said electro-magnet circuit when said controller is situated at any of its operative positions in advance of said selected operative position.

5. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to diflerent operative positions to cause circuits for transmitting power of increasing value to said motor successively to be closed, a contactor for controlling a circuit including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, and a regulator operative in response to advancement of said controller to said difierent operative positions to maintain substantially constant voltage at the terminals of said generator.

5. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to different operative positions to cause separate circuits for said motor successively to be closed, devices for causing power of increasing value to be transmitted to said motor in response to successive closing of said separate circuits, a contactor for controlling a circuit independent of the separate motor circuits and including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, and a regulator operative in response to closing of said separate circuits to maintain substantially '19 constant voltage at the terminals of said generator.

7. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to different operative positions to cause circuits for transmitting power of increasing value to said motor successively to be closed, a contactor for controlling a circuit including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, a regulator operative in response to advancement of said controller to said different operative positions to maintain substantially constant voltage at the terminals of said generator, and an interlock operable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position.

8. In combination, a prime mover, a generator driven thereby, an electric motor, an electro-magnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to different operative positions to cause circuits for transmitting power of increasing value to said motor successively to be closed, a contactor for controlling a circuit including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, a regulator operative in response to advancement of said controller to said difierent operative positions to maintain substantially constant voltage at the terminals of said generator, an interlock operable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position, and means for rendering said contactor incapable of closing said electro-magnet circuit when said controller is situated at any of its operative positions in advance of said selected operative position.

9. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to diiferent operative positions to cause separate circuits for said motor successively to be closed, devices for causing power of increasing value to be transmitted to said motor in response to successive closing of said separate circuits, a contactor for controlling a circuit independent of the separate motor circuits and including said electro-magnet, a circuit 'for said contactor, a manually actuable switch for controlling said contactor circuit, a regulator operative in response to closing of said separate circuits to maintain substantially constant voltage at the terminals of said generator, and an interlock operable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position,

10. In combination, a prime mover, a generator driven thereby, an electric motor, an electro-magnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a

controller adapted to be advanced step by step from a neutral position to different operative positions to cause separate circuits for said motor successively to be closed, devices for causing power of increasing value to be transmitted to said motor in response to successive closing of said separate circuits, a contactor for controlling a circuit independent of the separate motor circuits and including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, a regulator operative in response to closing of said separate circuits to maintain substantially constant voltage at the terminals of said generator, an interlock constituted as a solenoid in said contactor circuit and a stop element rigid with said controller operable when the contactor is conditioned to cause said'electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position, and means for rendering said contactor incapable of closing said electro-magnet circuit when said controller is situated at any of its operative positions in advance of said selected operative position.

11. In combination, a prime mover, a generator driven thereby, an electric motor, an electro-magnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to different operative positi'ons to cause separate circuits for said motor successively to be closed, devices for causing power of increasing value to be transmitted to said motor in response to successive closing of said separate circuits, a contactor for controlling a circuit independent of the separate motor circuits and including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, a regulator operative in response to closing of said separate circuits to maintain substantially constant voltage at the terminals of said generator, and an interlock operable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuation of the controller to any of said operative positions in advance of a selected operative position and when said contactor is conditioned to cause the electromagnet circuit to be open to permit actuation of said controller to operative positions therefor in advance of said selected operative position.

12. In combination, a prime mover, a generator driven thereby, an electric motor, an electro-magnet, output leads from said generator for feeding circuits for said motor and electro-magnet, a controller adapted to be advanced step by step from a neutral position to different operative positions to cause separate circuits for said motor successively to be closed, devices for causing power of increasing value to be transmitted to said motor in response to successive closing of said separate circuits, a contactor for controlling a circuit independent of the separate motor circuits and including said electro-magnet, a circuit for said contactor, a manually actuable switch for controlling said contactor circuit, a regulator operative in response to closing of said separate circuits to maintain substantially constant voltage at the terminals of said generator, an interlock constituted as a solenoid in said contactor circuit and a stop element rigid with said controller operable when the contactor is conditioned to cause said electro-magnet circuit to be closed to preclude actuat on Qf 2 1.8 QQntroller to any of said operative positions in advance of a selected operative position and when said contactor is conditioned to cause the electro-magnet circuit to be open to permit actuation of said controller to operative positions therefor in advance of said selected operative position, and means for rendering said contactor incapable of closing said electro-magnet circuit when said controller is situated at any of its operative positions in advance of said selected operative position.

13. In combination, a prime mover, a generator driven thereby, an electric motor, an electromagnet, output leads from said generator for feeding circuits fOr said motor and electro-magnet, a controller for a circuit to include said motor, a contactor for controlling a circuit to include said electrmmagnet, a holding circuit for said contactor, a regulator for normally maintaining substantially constant voltage at the terminals of said generator, a first switch adapted to be initially actuated to cause said contactor holding circuit and said electro-magnet circuit to be closed and voltage of value greater than normally supplied by said generator to be impressed upon the electro-magnet circuit, said first switch being adapted to be later actuated to cause voltage as normally supplied by the generator to be impressed upon said electro-magnet circuit,

and a second switch adapted to be actuated to cause said contactor holding circuit and said electro-magnet circuit to be opened.

DONALD C. GRAY.

REFERENCES CITED 7 The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 508,646 Thomson Nov. 14, 1893 598,731 Kubierschky Feb. 8, 1898 692,348 Reichel Feb. 4, 1902 1,616,037 Rushmore Jan. 30, 1912 1,182,231 Turbayne May 9, 1916 1,506,754 Hutchison Sept. 2, 1924 1,682,381 Kintzing Aug. 28, 1928 1,747,683 Shirk et a1 Feb. 18, 1930 1,786,815 Aspinwall Dec. 30, 1930 1,818,106 Stevens Aug. 11, 1931 2,036,516 Colanduoni Apr. 7, 1936 2,239,750 Weeks et a1 Apr. 29, 1941 2,283,785 Boling May 19, 1942 2,316,680 Ferri Apr, 13, 1943 2,370,856 Gray Mar. 6, 1945 2,371,555 Stamm Mar. 13, 1945 

